You've taken the first step of starting with what you do know. I would suggest starting with the following:
I started practicing Longfist without some of the fundamentals included on this DVD and my progress plateaued quickly. What I like about YMAA is that Dr. Yang stresses mastery of the fundamentals. This will set the foundation for your practice. I would suggest sticking with this one until you feel ready to progress to the next step:
This DVD will take you into the basics of Shaolin Longfist. There is a book on Shaolin Longfist that was published a while back. If you run across that one, I would use it along with the DVD. (I read somewhere on the forum that the DVD has information not included in the book).
Lastly, when you get an oppurtunity, try to find a qualified Longfist instructor that can help keep you on the right track. Hope that helps Ed...Train smart AND hard.